1. Field of the Invention
The present invention relates generally to a power plant, and more specifically to a synthetic gas (syngas) fueled power plant.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
A power plant used to produce electric power uses an industrial gas turbine engine (IGT) to drive an electric generator. The combustor burns natural gas to produce the hot gas flow that is passed through the turbine to drive the rotor shaft. An IGT is a very efficient power plant to convert chemical energy from burning a fuel into mechanical energy through a turbine to drive a rotor shaft.
Coal is presently used to power a power plant. Coal is an abundant and cheap source of energy. However, coal is considered a dirty fuel because of the toxic chemicals present and the CO2 and NO2 products left over from the combustion. Synthetic gas (or syngas) is made from coal or biomass and burned as a fuel in a gas turbine engine to produce power. The syngas is clean energy and therefore would produce electric power without leaving the contaminated exhaust as is found in burning raw coal. Ethanol and methanol is produced from syngas in a catalytic reaction under very high pressure (e.g. 1,200 psia). The high pressure gas exiting the Fischer/Tropsch process is brought down in pressure low enough to be used in the combustion chamber of the IGT. Lowering the pressure of the syngas is typically done through a pressure reduction valve, and therefore the energy contained in the high pressure gas is wasted. In production of the syngas that is used to produce the ethanol or methanol, about 5% of the syngas is bled off and used to power the gas turbine engine. The gas turbine engine produces electric power used to produce the ethanol or methanol from the 95% syngas.
The production of alcohol fuels, such as ethanol or methanol, is from a biomass where the biomass is passed through a gasifier and air, oxygen or steam (or a combination of these three ingredients) is used to produce a relatively low pressure syngas. The low pressure syngas is cooled and then raised to a relatively high pressure of around 1,200 psia. This high pressure syngas is then passed into the Fischer/Tropsch reactor to produce the alcohol fuel. Around 95% of the high pressure syngas is converted into the alcohol fuel in the Fischer/Tropsch reactor while the remaining 5% of the syngas is left over from the reaction.